Mr. Sidharth Goutam Dash
Regd. No.: 0901106181
Prof. Dr. A. Mohapatra
Prof. Dr. R.K. Jena
As our world becomes even more dependent on electrical
and electronic equipment, there is an increased likelihood
that operations will experience the negative effects of
The productivity and efficiency gains achieved from
increasingly sophisticated pieces of equipment have
a drawback: increased harmonic distortion in the
electrical distribution system.
Harmonic mitigating transformers (HMTs) are a
leading solution to eliminate these harmful
harmonics and improve your system reliability.
Sources of Harmonics
General sources of harmonics
• Power electronic equipment
(drives, rectifiers, computers, etc.)
• Arcing devices (welders, arc
furnaces, florescent lights, etc.)
• Iron saturating devices (transformers)
• Rotating machines (generators)
Most prevalent and growing harmonic
• Adjustable frequency drives (AFD)
• Switch-mode power supplies (computers)
• Fluorescent lightning
Symptoms of harmonics
•Over-loaded neutral conductors
•Over heated motors and transformers
•Blown fuses or breakers tripping repeatedly
•Failure of power factor correction capacitors
Timing errors in sensitive electronic
What do HMTs do?
HMTs are an economical solution in the
battle against the harmful effects of
HMTs are highly reliable devices; they
don’t have any moving parts and they are
typically energized 24/7, 365 days a year.
This means that they are always “on the
job” treating harmonics, regardless of the
level of load they are serving at a given
point in time. Whenever the HMT is
energized, it will provide harmonic
A typical HMT
Principle of HMT
Harmonic mitigating transformers use phase-shifting
, electromagnetic flux cancellation, and source
impedance to reduce harmonic currents in electrical
distribution systems. By reducing the amount of heat that
harmonics generate, these devices enable transformers to
operate at lower temperatures. The result is lower cooling
costs as well as longer device life and reduced maintenance.
Harmonic mitigating transformers also enable the use
of a transformer’s full capacity and ensure compliance
with harmonic limits defined by the Institute of
Electric and Electronic Engineers and other
Parts of a HMT
Usually a HMT consists
of five parts
Core & Coil Assemblies
Infrared heat scans
of transformers when feeding the same
non-linear, computer load.
•Reduces the K-Factor Ratio of the loads.
•Prevents distribution system apparatus from overheating.
•Balances phase currents and voltages on primary.
•Reduces voltage distortion.
•Increases system capacity and reliability.
•Reduces apparatus vibration and noise.
•Prevents electronic circuit breaker malfunctions.
•Provides a healthier environment for the loads.
MARKETS FOR HMT:
1 .EDUCATIONAL FACILITIESSchools and colleges have laboratories that contain
an ever-increasing number of
electronic devices which give rise to Harmonics. In
educational institutes HMTs
can be installed.
2. COMMERCIAL FACILITIESIn commercial office-buildings, customer service
call-centers, insurance companies, government offices,
presence of computers, printers and copying machines
create an environment that is full of Harmonics.
Installing HMTs can prevent losses.
3 .RETAIL FACILITIESElectronics and appliance stores as well as plaza
and malls and grocery stores typically make use
of electronic devices. HMTs can be used in these
places to avoid harmonics.
4 .MEDICAL FACILITIESThese are the ideal locations for HMTs. Most modern diagnostic and analysis
equipments are electronic. Excessive harmonics may cause personal records or
medical test data to be corrupted or destroyed.
5.GAMNG INDUSTRYHMTs can be beneficial in
casinos, racetracks and offtrack-gaming parlors.
HMTs are a cost effective means of treating harmful
Reducing harmonic content in electrical systems can
result in a more reliable electrical system ,
lower maintenance cost ,less equipment malfunction
and lower cooling capacity.
In short , taking HARM out of HARMONICS
was never this easy .